iOS ui--about modal

The modal effect shows:

About the modal of knowledge points involved:

1, when a controller is destroyed, it all the sub-controller business logic can not be processed

2, when a controller is destroyed, it all the child control of the business logic can not be processed

3, when the controller is destroyed, the controller's view is not necessarily destroyed

4, Self.presentedviewcontroller will be strong reference modal out of the controller

Get another controller through UIApplication in another controller, because UIApplication is a singleton class and can be obtained globally, so:

UIWindow *keywindow = [uiapplication shareapplication].keywindow;//get UIWindow Object

iOS ui--about modal